There are several disparate technologies that provide a partial solution to this problem. Self-balancing single axle devices, such as electric unicycles, Segway® and hover-boards can provide transportation over substantially flat terrain and have a reasonable range, but they are easily stopped by steps, curbs and other street furniture. Furthermore, they are too heavy and bulky for easy stowage and therefore they do not integrate well with other transport solutions as they occupy too much space within a vehicle, if, indeed, they can even be successfully stowed within the vehicle.
There are also two axle systems, which have the potential to be more stable than single axle systems. However, they also fail to address the issue of changes in height at curbs, steps and gaps.
Stair-walkers and other similar three-wheel cluster devices have been developed specifically to deal with stairs. However, they are typically too heavy and bulky for stowage within a vehicle or integration with other transportation solutions.
It is against this background that the present invention has arisen.